Purpose:
Posterior Capsule Opacification (PCO) is a disease that occurs in some adults and most children following cataract surgery. In the fibrotic form of PCO, myofibroblasts migrate onto the posterior capsule and contract to produce wrinkles that affect visual acuity. We have discovered a subpopulation of cells in the human lens that expresses the skeletal muscle specific transcription factor MyoD and bone morphogenetic protein inhibitor Noggin. These “Myo/Nog” cells also can be distinguished with the G8 monoclonal antibody (mAb). Depletion of Myo/Nog cells with the G8 mAb and complement prevents the accumulation of myofibroblasts in explants of human lens tissue. The goal of this study was to test an innovative method of cytotoxic targeting that utilizes 3DNA nanocarriers complexed with the G8 mAb

Methods:
Anterior human lens tissue was obtained by capsulorhexis and cultured in serum free medium. Tissue was fluorescently labeled with antibodies to skeletal muscle proteins. Anterior lens explants were incubated with the G8 mAb complexed with 3DNA intercalated with the cytotoxin Doxorubicin (G8-3DNA-Dox), G8-3DNA or 3DNA-Dox. Cells were incubated with G8-3DNA labeled with Cy3 and Lysotracker dye to determine whether the complex was incorporated into acidic compartments of the cell. Explants treated with G8-3DNA-Dox or control complexes were assayed for apoptosis by labeling with TUNEL reagents.

Results:
Myo/Nog cells were enriched around cell free areas of the capsule and expressed MyoD, sarcomeric myosin, the T-tubule associated 12101 antigen, troponin T and alpha smooth muscle actin. Some cell free regions lined by Myo/Nog cells contained a wrinkle in the capsule. G8-3DNA was internalized into acidic compartments of Myo/Nog cells, an obligatory step for the release of Doxorubicin. Incubation with G8-3DNA-Dox specifically targeted and induced apoptosis in Myo/Nog cells. Control conjugates of G8-3DNA and 3DNA-Dox did not induce apoptosis in Myo/Nog or lens epithelial cells.

Conclusions:
Antibody-3DNA nanocarriers are specific and efficient reagents for delivering cytotoxic cargo into a subpopulation of cells. The 3DNA nanocarriers themselves are nontoxic reagents. Administration of G8-3DNA-Dox at the time of cataract surgery may reduce the incidence of PCO, maintain visual acuity and reduce healthcare costs.